Nowadays, in order to use a mobile telephone terminal, a telephone subscriber identification card is to be inserted within it. Such card is generally called UICC [Universal Integrated Circuit Card]; for GSM [Global System for Mobile communications] the UICC contains a SIM [Subscriber Identity Module] application and for UMTS [Universal Mobile Telecommunications System] the UICC contains a USIM [Universal Subscriber Identity Module] application; UICC may contain several applications, making it possible for the same card to give access to e.g. both GSM and UMTS networks and also to provide storage of other applications and/or of user data, for example a phone book.
Telephone subscriber identification cards securely store not only subscriber identification information but also subscriber authentication information; for example, a SIM card stores an IMSI [International Mobile Subscriber Identity] code and a KI [Authentication Key] code.
A mobile telephone operator provides its subscribers with at least a voice communication service and very often other services like data communication services (e.g. GPRS [General Packet Radio Service], WAP [Wireless Application Protocol] internet navigation, FTP [File Transfer Protocol] download or upload, SMS [Short Message Service] transfer, MMS [Multimedia Messaging Service] transfer, DVB-H [Digital Video Broadcasting—Handheld] reception), entertainment services (e.g. playback of multimedia content protected by DRM [Digital Rights Management]) and other more specific services. A user may be subscribed (i.e. enabled) to one or more of these services and is generally called a subscriber.
A subscriber may pay the subscribed services basically in two different ways: in credit mode or in debit mode; in debit mode, the subscriber pays money before using services and accumulates a credit that can be used afterwards; in credit mode, the subscriber uses services and accumulates a debit that can be settled afterwards. The payment mode is part of the user subscription with the mobile telephone operator.
It may happen (A) that a subscriber would like to use one of his subscribed services but he has no or not enough credit or (B) that a subscriber would like to use one of his subscribed services but he does not want to pay for it.
In these cases, a first option for the first subscriber is to ask a second subscriber to use his mobile telephone terminal (this option may be used if the second subscriber is subscribed to the service of interest to the first subscriber); a second option for the first subscriber is to ask a second subscriber to extract the telephone subscriber identification card from the mobile telephone terminal of the second subscriber and then to insert it into the mobile telephone terminal of the first subscriber (this option may be used if the service of interest to the first subscriber does not require any specific information that is securely contained in the subscriber identification card of the first subscriber).
Both options are awkward and can not always be used.
Patent application WO 03/084265 discloses a method and an apparatus for accessing a network using remote subscriber identity information. Subscriber identity information in a memory within a device such as a mobile terminal can be remotely used by a second independent device. In the case of a GSM terminal, for example, one terminal would be able to utilize the subscriber identity information contained in the subscriber identity module (SIM) of another terminal by establishing a local communication link between the two terminals. Remote subscriber identity information is transferred over the local communication link and the communication terminal, which is using the remote subscriber identity information, can register with the telephone network using that information, thus, eliminating the need to transfer the SIM.
The idea of using subscriber identity information located or locatable remotely from the mobile telephone terminal was known even before the above mentioned patent application.
Patent application WO 99/59360 discloses an arrangement for communication of subscriber identity module related data in a wireless communication system. The arrangement comprises a wireless communication terminal with a subscriber identity unit which is adapted to comprise a subscriber identity module to which a subscriber identity is assigned. This patent application discloses also a method for communication of subscriber identity module related data in a wireless communication system for implementation in a wireless communication terminal with a subscriber identity unit. The subscriber identity unit is arranged to communicate the subscriber identity module related data such as the subscriber identity with the terminal over a local wireless communication link. The arrangement according to this patent application makes it possible to separate the subscriber identity unit from the terminal while the terminal is communicating in the wireless system.
Patent application US 2003/0211861(now U.S. Pat. No. 6,985,756) discloses an apparatus and a method that provide remote access to subscriber identity information and subscriber configuration information stored on one or more subscriber identity modules (SIMs) in order to allow remote configuration of wireless communications devices. A SIM server provides access to the SIMs, a SIM librarian catalogues the SIMs, and a SIM accounting system tracks and/bills for SIM usage. The apparatus and method provide remote access to proxy wireless communications devices, allowing such devices to operate as if actually present in the remote locations.